Time Model¶
The Time Model in OEE is a representation of the production time and various downtimes of a plant. It describes the categorization of the total time of a plant into different time categories, which represents the time consumption in the plant. By default, the Insights Hub OEE application has three major time categories for the calculation of overall equipment effectiveness. Using these time categories, users can derive their own sub-categories.
The main time categories of the Insights Hub OEE application are:
- Production Time: This category includes the run time of a machine or a line.
- Planned Stop: This category contains all stops that are scheduled for production, for example, a planned maintenance, shift break, holiday, or a weekend, where the machines and lines are not producing. These times are not considered for the calculation of OEE, but are important for the calculation of the Total Effective Equipment Performance (TEEP). Furthermore, no OEE is calculated during planned stops.
- Downtimes: This category includes all the various machine or line stop states that lead to the loss of productive time within their schedule. This typically includes all types of downtime, change-over, cleaning phases, supply chain-related issues, or internal faults. These stops are always classified as an Availability Loss unless it is a Microstop. In the case of Microstops, the user can decide whether it should be classed as an Availability or Performance Loss.
The table below illustrates the impact of each major time category on the corresponding KPIs.
| KPI | Production Time | Availability Loss | Planned Stop |
|---|---|---|---|
| OEE | X | X | |
| TEEP | X | ||
| Availability | X | X | |
| Performance | X | ||
| Quality | X | ||
| MTTR | X | X | |
| MTBF | X | X |
The formulas for the KPIs calculation are described in the section OEE Standard Formulas.
The below graphic explains the time model.
In this example, ten different time categories are defined, which are inherited from the following three major time categories:
- Production time: Under Production time, a one-time category called Run is defined which represents when the machine or line is operating.
- Planned Stop: In this time category, multiple categories are defined that stand for different stops in a factory, which are holiday, shift break, maintenance, and no production. Whenever the machine status or configured calendar for a machine or line is in one of these time categories, then these times are counted towards the Planned stop and are not considered in the overall OEE calculation.
- Downtimes: Under Downtimes, we have a fixed category called Microstops defined as short stops that are below the configured threshold. Microstops can be configured as either Availability or Performance loss by refering to section Configuring Microstops. Other time categories represent typical Availability Losses. In this case, we have defined Cleaning, Run Down, Start-Up and Unplanned Downtime. Whenever we are in a machine or line state that is represented by one of the above-mentioned time categories, then this time is counted towards Availability Loss.
The definition of the time model is a crucial step to evaluate and understand the collected machine status. For more information to set up the time model, refer to Configuring Time Model.
The states defined under Production Time and Planned Stop can also be utilized in the Calendar configuration to describe the machine schedule. For more information, refer to Configuring Calendar.
The Reason Tree section shows how the underlying time model can be utilized to build custom reason trees.